This invention relates to polyol compositions, and polyurethane systems, coatings, adhesives, sealants, elastomers, binders, resins, and prepolymers made up of polyol compositions and more particularly to polyol compositions and polyurethane systems containing high amounts of renewable raw materials, and methods of making and using the same.
At the present time foams and polyurethane plastics are made by reacting a polyol with an isocyanate with a functionality of at least 2 (two) or greater. The polyol can be a polyester molecule which has at least a functionality of at least 2 (two) or greater. The polyol can also be a polyether polyol which is made by reacting propylene oxide, ethylene oxide, butylene oxide, or derivatives of molecules such as epichlorohydrin with a molecule such as ethylene glycol or glycerine to produce molecules with various molecular weights, which have pendant Hydroxyl groups and will react with difunctional or multi-functional isocyanates to produce a solid plastic or foam.
At the present time, to produce a rigid foam or a polyurethane plastic it is necessary to react one part isocyanate with one part polyol. This reaction with the isocyanate makes the polyurethane product. A disadvantage of the use of isocyanate is that when the foam is burned, high levels of toxic gases are produced which are generally derived from the isocyanate part of the molecule. In addition, to facilitate the optimal physical and chemical properties of the final polyurethane foam product, additives including blowing agents, surfactants, flame retardant, catalysts, and fillers may be used to facilitate the reaction between the polyol and the isocyanate.
The use of polyurethane reactions to make plastic material is well known in the art, for example as described in both the “Polyurethane Handbook”, 2nd edition, edited by G. Oertel, Hanser Publishers, 1993, expressly incorporated herein by reference, and “Riegel's Handbook of Industrial Chemistry”, 1983, pp. 372, expressly incorporated herein by reference.
Polyurethanes are a versatile plastic material which can be used in a variety of industrial applications. New market opportunities and business conditions are creating increased need for new materials that provide optimal physical performance while meeting increasing environmental, legislative, and cost requirements. Environmental concerns leading to the phaseout of halogenated blowing agents including chlorofluorocarbons (CFC's), hydrochlorofluorocarbons (HCFC's), and hydrofluorocarbons (HCF's) has led to for more competitive performance of polyurethane in the areas of insulation and flame resistance while meeting environmental mandates.
Further, price increases of petroleum which is used as both a raw material and energy source in production of polyurethanes has also led to increased new for polyurethane formulators to provide solutions that maintain physical performance while being cost effective. A source of opportunity for addressing these needs has been the use of hydrocarbon blowing agents to replace the halogenated blowing agents and new renewable raw materials including agricultural co-products based on vegetable oil and potentially provide an alternative to the price volatility of petroleum based raw materials.
In order to ensure the final polyurethane has the optimal properties and the components have the desired effect increasing attention is being given to additives which can have a large impact on the final properties of the foam. In particular, additives which can make hydrocarbon blowing agents more compatible with standard rigid foam formulation mixtures are of increasing importance. It is an object of this application to address additives, new polyurethane materials, and methods for using additives and new polyurethane materials that may make polyurethane components more compatible and optimize the properties of the final product. Properties of the final product and reaction parameters which are of increasing importance include density reduction with a cost effective amount of environmentally responsible blowing agent. Flame resistance, thermal conductivity, thermal aging characteristics, strength characteristics, and cost are other important considerations that are being evaluated as formulations are being developed to address new market concerns.
In addition, rising costs of petroleum has led to increasing costs of raw materials in the chemical industry and has prompted interest for ways to provide cost stability to customers. In polyurethane applications, adjustments to conventional petrochemical formulations can provide savings in one of five main methods: 1) Decrease amount of isocyanate used; 2) decrease density of overall polyurethane part without a decrease in physical properties; 3) decrease amount of polyol used without a decrease in physical properties; 4) decrease costly additives; and 5) improve processability. In the article entitled “Low Hydroxyl Number Polyester Polyols for Lamination” by Richard Donald et al, describes how one end user group in the polyurethane industry, polyiso laminators, responded to the shortage of polymeric isocyanate and the resulting rising costs by making adjustments to lamination formulations. Typically, isocyanates are more expensive than the polyol components of polyurethane products. By reducing the amount of isocyanate used in the formulation in a cost savings can be made. Further, when the isocyanate supply is reduced these savings are even more critical.
In addition, use of, environmentally friendly, and energy efficient plant components, has introduced new concerns for processing, new questions for polyurethane formulations, and increasing need for compatibility among all polyurethane formulation components. In particular, it is of increasing importance to be able to utilize new polyurethane raw materials in the same way, previous petrochemical based raw materials are used and to have renewable raw materials in the same range of consistency for quality assurance properties. Vegetable oils may require additional processing which leads to increased expense, time, and energy consumption to reach a point where it is more suitable for industrial application. These oils derived from plants require a step to pass air through the oil to oxidize or functionalize the oil with Hydroxyl groups (—OH). Soy oils have been epoxidized in U.S. Pat. No. 5,482,980. US Patent Pub. 20070123597 A1 notes that in addition to fatty acid triglycerides, soy polyols contain low molecular weight species, such as aldehydes and hydroperoxides, which lead to unpleasant odor and prevents their use in automotive applications.
In addition, to adding cost, time, and energy expenditures for these additional processing steps, the resulting material still may result in unsatisfactory final properties when used in polyurethane applications. Polyurethane foam and plastic products, derived from biobased oils are still noted to be flexible and not have the same rigid strength as petrochemicals derived from conventional petrochemical based polyols. In addition, polyurethane formulators are attempting to develop complete biobased systems that can be applied in the same way as conventional polyurethane systems. This has proved difficult due to the differences in formulation and properties which require changes in processing, production, and application. There is a need for renewable raw materials which are versatile, well understood, easy to apply, and consistent to produce and use.
It has been discovered that using a biobased component from another agricultural feedstock can result in a biobased polyol and final plastic product with more of the desired properties. Further, utilization of this abundant natural material rich in aromatic compounds may reduce the need for antioxidant additives to reduce odor, flame spread, improve UV resistance, or act as a biocide. This group of materials in one form is known as lignin. Lignin may also increase the thermal and chemical resistance properties of the final product. The improved thermal properties may include improved thermal conductivity, decreased flame spread, increased char formation; reduced odor, improved heat distortion, improved heat sag, and increased UV resistance.
After cellulose, lignin is one of the most significant components of vascular plant tissue by weight. It is widely available in industrial quantities and is considered a by-product of many high volume industrial processes. At an industrial level in most cases lignin is consumed as fuel, where it is utilized only for its fuel value. Lignin has a unique chemical structure with valuable functional groups which can be utilized in other applications.
The lignin molecule can be used to provide aromatic functional groups which can provide greater strength and rigidity to the polyurethane foam.
In addition, the renewable polyol has increased renewable raw material content and can act as a more versatile polyol in a variety of industrial applications.
The use of the lignin molecule may also significantly improve the moisture resistance of a foam. In fact, when the proper level of lignin is used in a polyurethane foam, the polyurethane foam may have increased water resistance.
Additionally, the electron rich structure of many renewable raw materials derived from biomass sources including lignin provides valuable antioxidant activity.
This antioxidant activity may lead to increasing flame resistance, UV stability, thermal resistance, chemical resistance, improved adhesion, increased rigidity, and increased strength.
In addition, the presence of the lignin can protect the polyol from oxidative degradation at higher temperatures during processing or storage reducing the release of unwanted volatile breakdown components which can be malodorous.
This combination of vegetable oil and aromatic group containing materials from renewable raw resources can lead to increased cost savings, higher yield of useful portion of plant, and more versatile use in a greater number of chemical and plastic markets.
U.S. Pat. No. 3,519,581 (incorporated herein by reference) discloses dissolving lignin in a substantially non-volatile solvent before reacting with a polyisocyanate.
U.S. Pat. No. 3,654,194 (incorporated herein by reference) discloses oxyalkylation of lignin before reacting with an isocyanate.
U.S. Pat. No. 4,987,213 (incorporated herein by reference) discloses the reaction of a solvent solution of lignin with a polyisocyanate compound.
U.S. Pat. No. 6,025,452 (incorporated herein by reference) discloses the reaction of a lignin material with a S content with a polyisocyanate compound.
U.S. Pat. No. 6,054,562 (incorporated herein by reference) discloses the blending of a lignin with a polyether or polyester resin to improve the melt and flow properties.
U.S. Pat. No. 5,196,460 (incorporated herein by reference) discloses the use of lignin with rubber as a tackifier.
U.S. Pat. No. 4,764,596 (incorporated herein by reference) discloses the process of recovering an organosolv lignin.
U.S. Pat. No. 4,546,124 (incorporated herein by reference) discloses methods for altering structure of a phenolic resin to improve strength of a resin in foundry applications.
U.S. Pat. No. 7,109,285 B2 (incorporated herein by reference) discloses methods for synthesizing polyurethane prepolymers for producing polyurethane polymers.
U.S. Pat. No. 6,180,686 (incorporated herein by reference) to Kurth discloses a cellular plastic material comprising the reaction product of soy oil, a crosslinker, and an isocyanate.
U.S. Pat. No. 6,624,244 (incorporated herein by reference) to Kurth discloses an improved material comprising the reaction product of a vegetable oil and an isocyanate.
U.S. Pat. Pub. 20030083394 A1 (incorporated herein by reference) to Clatty discloses foams with improved heat sag and heat distortion temperatures.
U. S. Pat. Pub. 20020192456 A1 (incorporated herein by reference) to Mashburn et al. discloses a carpet backing comprising a polyisocyanate and a mixture of vegetable oil.
U.S. Pat. Pub. 20050282921 A1 (incorporated herein by reference) to Flanigan et al. discloses a cellular material comprising the reaction product of a soy-based polyol, petro-based blowing agent, cross-linking agent, combination of silicone surfactants, and an isocyanate.
U.S. Pat. Pub. 20070123597 A1 (incorporated herein by reference) to Perry et al. discloses a cellular material comprising the reaction product of a soy-based oil exposed to ultra-violet light and an isocyanate.
U.S. Pat. No. 6,420,443 B1 to Clark et al. (incorporated herein by reference) discloses composition for enhanced compatibility in rigid polyurethane foam systems.
U.S. Pat. No. 7,393,465 (incorporated herein by reference) discloses compositions for hydrophobic polyols recovered from renewable feedstocks which are reacted with alkylene oxides.
U.S. Pat. No. 7,268,183 to Wintermantel (incorporated herein by reference) discloses polyurethane compositions for use in pressure sensitive applications.
The article entitled “Low Hydroxyl Number Polyester Polyols for Lamination” by Richard Donald et al. (incorporated herein by reference) describes low Hydroxyl polyester polyol formulations results in laminator plant trials.